Method of forming articles from pressed metal.



A L. PUTN'AIVI.

TICLES FROM PRESS'ED METAL.

FILED FEB,23|1916.

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mom/I301 $51, Aha Fmmm Patented 00f. 31,1916.

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ALDEN L. PIITNAM, 0F DETROIT, MICHIGAN, ASSIGNOR T0 DETROIT PRESSED STEEL COMPANY, 013 DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

METHOD OF FORMING ARTICLES FROM PRESSED Specification of Letters Patent. 7 Patented @6113. 31L, 19TH.

Application filed February 23, 1916. Serial No. 79,809.

T0 all whom it may concern:

Be it known that T, 'ALDE'N L. PUTNAM, .a citizen of the United States of America, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Methods of Forming Articles from Pressed Metal, of which the following is a specification, reference being had therein, to the accompanying drawings.

The invention relates to the manufacture of articles from pressed metal, and it is the object of the invention to produce'structures which cannot be formed from uniform gage sheet-metal blanks. For instance, in the formation of many articles of cast-metal it is advantageous to rib or emboss the structure in various places to increase the strength thereof, and while the general form of the structure can be fashioned from sheetmetal it is practically impossible to produce such ribs and bosses. T have therefore devised a method of producing a ribbed or embossed structure from pressed wrought metal as hereinafter set forth.

In the drawings T have shown my improved process as applied to the manufacture of pressed sheet-metal engine piston, in which Figure 1 is a plan view of the blank forming the first step in the process; Fig. 2- is a cross-section on line .22 Fig. 1; Fig. 3 is a vertical central section through the pressing and forming dies showing the blank before the pressing operation; Fig. 4 is a longitudinal section through the piston after the completion of the pressing operation; Fig. 5 is a similar view in a plane at right angles to Fig. 4; and Fig 6 is a bottom plan view.

Broadly described, my improved process comprises the formation of a ribbed or embossed but otherwise comparatively fiat blank, by drop forging or equivalent means, and in then pressing said blank to re-fashion the same into its final form. With the specific structure shown, A is a circular blank formed by drop forging and fashioned to have a central portion B with radial ribs C and a central boss D. Surrounding the por tion 18 is an annular portion E of greater thickness and at the point of chan e of gage of the metal is a curved fillet F. gurrounding the annular portion E is another annular portion G, and at two diametrically op posite points there are formed onthis portion G the hollow bosses H. All of the portions of the blank as above described can be readily fashioned by drop forging', as the draft is all in one direction.

To impart a cupped form to the blank it is pressed in suitable dies, such as the ring die I and the plunger die J. The latter is formed of a central portion K and a series of separable segments L surrounding the same, said segments upon diametrically opposite sides beingcut-away at M to form a pocket for receiving the bosses H. The central ortion of the plunger K isenlarged above t e segments L to form a shoulder N for bearing thereagainst, and this shoulder is also cut-away at O to form a complementary portion of the recesses for receiving the bosses H.

Tn performing the pressing operation the blank is centered by the engagement of the central embossed portion D with a recess P in the end of the plunger,.. and as the metal is forced down in the annular die I the outer peripheral portion G is bent upward or cupped. This. cupping operation may be repeated with a series of annular dies of different diameter until the portions E and G of the blank "become cylindrical 1n form, the portion E being of greater thickness than the portion Grand occupying an annular recess Q in the segmental dies L. The bosses H are also forced into the recesses M and 0 so as to be in axial alinement with each other. The hollow piston thus formed has a ribbedhead portion 7 formed of the portion B, a thick cylindrical wall' adjacent thereto formed of the portion E and a thinner wall formed of the portion G. Both the portions E and G may be readily fashioned into the cylindrical form with the exception of that part of the portion G from which the boss H projects, but the rigidity imparted to the structure at this point would render the bending of the same difficult. I therefore form in the original blank a segmental portionR upon the opposite side of the blank from the' I plunger from the cup because of the interlocking with the bosses H. With the sectional plunger, however, the several sections may be separately removed without difficulty. I

The pressed metal structure formed as described may be completed by the usual machining operation of boring the bosses H and cutting annular grooves S in the heavy wall E for receiving the piston rings. The boss D also provides metal for a center for turning the piston and may be removed subsequent to the machining operation.

thickness distributed with respect to predetermined positions in the completed article, and drawing the blank to re-fashion the thinner portions thereof and to re-arrange the thicker portions.

2. The method of forming pressed metal articles, comprising the forming of a substantially circular blank with a re-fashionable thin portion and a plurality of projecting thickened portions fashioned to final form, and drawing the blank to re-fashion said thin portion and to re-arrange the thickened portions.

3. The method of forming pressed metal articles, comprising the preliminary forming of a substantially circular blank by drop forging, said blank having re-fashionable thin portions and thick portions fashioned to final form, and drawing said blank to re-fashion the same and re-arrange the thick portions.

4:. The method of forming pressed metal articles, comprising the forming of a comparatively thin substantially circular blank with a plurality of projecting thickened portions fashioned to a final contour. and drawing the blank to re-fashion the thin portion to be complementary to the pre-fashioned thickened portions.

5. The method of forming pressed metal articles, comprising the forming of a comparatively thin blank by drop forging, said blank being provided with radially-extending thickened ribs and projecting thickened embossed portions, and pressing said blank to cup the same.

6. The method of forming pressed metal articles, comprising the forming of a comparatively thin blank by drop forging, said blank having an annular thickened portion with thin portions on opposite sides thereof, and pressing said blank to cup the same, forming the head of the inner thin portion and a cylindrical wall of the intermediate thickened portion and outer thin portion.

7. The method of forming pistons, com-- prising the forming of a drop forging having a central thin portion, a surrounding annular thickened portion and an annular thin portion surrounding said thickened portion, being also provided with projecting thickened embossed portions, and pressing said blank to draw said annular thick and thin portions into cylindrical form and to arrange said embossed portions transversely in alinement with each other.

8. The method of forming pistons comprising the forming of a substantially Hat blank having a comparatively thin center portion reinforced by radial ribs, and the drawing of the outer portion of the blank to form the cylindrical wall of the piston.

9. The method of forming pistons, comprising the forming of a drop forging having projecting thickened embossed portions, and pressing said blank to draw its outer portion into cvlindrical form and to arrange said embossed portions transversely in alinement with each other.

In testimony whereof I affix my signature.

ALDEN L. PUTNAM. 

